1. Field of the Invention
The present invention relates to a method of mounting an electronic component, such as a ball grid array (BGA) semiconductor package. In particular, the invention relates to a method of mounting an electronic component on a substrate by melting a conductive bonding material on a terminal pad on the substrate.
2. Description of the Prior Art
Some methods of mounting an electronic component on a substrate utilize a solder paste. The solder paste is previously printed on terminal pads disposed on the surface of the substrate. Terminal conductors, such as solder balls, of the electronic component are placed on the corresponding terminal pads. After the electronic component has been set on the substrate in this manner, the substrate is passed through a reflow oven. Solder particles dispersed within the solder paste are caused to melt in the reflow oven. Subsequent cooling treatment serves to solidify the solder on the terminal pads on the substrate. The terminal conductors of the electronic component are thus bonded to the corresponding terminal pads on the substrate.
The solder paste usually includes an organic solvent. When the solder particles melt in the solder paste, the organic solvent is forced to vaporize in the melting solder. In this case, the vaporized or gaseous organic solvent is locked within the melting solder in the aforementioned conventional method, since the surface of the solder paste is covered with the terminal conductors of the electronic component. Voids remain within the solidified solder. The voids may cause a failure in electric contact between the electronic component and the substrate. The voids are supposed to reduce the strength of bonding between the electronic component and the substrate.